U.S. and Dutch authorities have moved to halt alleged international mail fraud schemes suspected of bilking millions of dollars from elderly and vulnerable victims in the U.S. and around the world.

The Department of Justice said Thursday that U.S. residents received fraudulent mail solicitations that falsely claimed recipients had won or would soon win cash or other valuable prizes.

Unwitting victims sent payments via U.S. and international mail to two Dutch companies in Utrecht: Trends Service in Kommunikatie B.V. and Kommunikatie Services Buitenland, B.V. Both are owned and operated by Erik Dekker, 54, of Langbroek, Netherlands, authorities said.

A civil court complaint filed Wednesday against Dekker and the companies charged that solicitations were mailed to U.S. residents since at least 2012 from locations around the globe. Purporting to be personalized mailings, some instructed recipients to pay a processing fee to receive lottery winnings or other prizes, the complaint charged. Others allegedly urged purchases of goods or services based on false promises of future lottery wins.

Victims responded by submitting $15 to $55 in envelopes pre-addressed to more than 50 Netherlands postal boxes that the court complaint said were operated by the Dutch companies.

U.S. victims mail more than $18 million annually to the postal boxes in response to the solicitations, the Department of Justice estimated.

U.S. District Judge I. Leo Glasser in Brooklyn, N.Y. on Wednesday approved a temporary restraining order to halt the solicitations.

Separately, the Netherlands Fiscal Intelligence and Investigation Division searched 10 locations in a criminal investigation of six Dutch companies suspected of links to the alleged fraud. The companies are believed to have facilitated a scam that sent millions of phony solicitations to residents of the U.S., Great Britain, Switzerland, Italy, France, Japan and other countries, the Dutch investigative agency said.

The fraud's chief operators are believed to be outside the Netherlands, the agency said.

"Schemes targeting elderly victims are increasingly international in scope, but geographic distance will not prevent us from seeking justice and holding bad actors accountable," Principal Deputy Assistant Attorney General Benjamin Mizer said in a statement.

Anyone who receives a solicitation that requires a fee to collect a prize should be wary, said Regina Faulkerson, Inspector in Charge at the U.S. Postal Inspection Service. "When that happens, it's fraud — plain and simple," she said.